| Description |
Structural specifications define an abstract object as a composition of other abstract objects. Behavioral specifications define an abstract object in terms of its associated operations. Integrated specifications are a combination of structural and behavioral specifications which are more powerful than either used alone. By providing four naming mechanisms, integrated specifications hide the details of how objects are represented and accessed on storage devices. The four naming mechanisms allow objects to be named in terms of the operations previously applied to them, the unique attributes they possess, the relationships they participate in, and the categories they belong to. Integrated specifications can specify the structure of more abstract systems than the relational database model, while also characterizing dynamic properties. Examples are given of integrated specifications for quide, symboltable and expression. These specifications are simple and guide, but do not constrain, the implementor in designing refinements. By exploiting abstract structure in specifications, common aspects of inter-object communication can be suppressed and only salient differences emphasized. Integrated specifications can make a significant contribution to the useability, reliability and efficiency of computer systems. |
